Supplemental information: Guidelines from health experts

How do I choose a multivitamin?

Generic and brand name vitamins usually contain similar ingredients. Some may have forms of vitamins that are easier to absorb than others, but considering that you may be taking these pills every day for the rest of your life, cost should be your first priority. Look for a budget-friendly product that contains no more than 100% of recommended daily values of essential vitamins and minerals. Too much of these substances — especially iron, vitamin A and zinc — can be toxic.

When should I consider supplementing my multivitamin with more vitamins or minerals?

If you are a heavy exerciser, you might need extra vitamins and minerals, especially iron, vitamin C and E. Women of childbearing age need to get enough folic acid. Menstruating women need more iron than others. Older women often need extra calcium because of lowered acidity in their stomachs, and B12 can help the hearts of elderly people. Evidence is growing that everyone needs more vitamin D.

How should I store my vitamins?

Keep them in a cool, dark place such as a kitchen pantry. Unless the label indicates otherwise, there is no need to keep them in the fridge. (Some supplements, such as fish oils, can become rancid unless refrigerated.) Storage in steamy bathrooms isn't ideal. And, of course, keep vitamins away from kids.

How long will my vitamins last?

If you want to be sure they're potent, don't keep them past the expiration date. No expiration date? Don't buy it.

Why are vitamin pills often so large?

There's a lot of stuff in there! The more nutrients inside, the bigger the pill. Protective layers and time-release coatings can also bulk a vitamin up.

Can I chew them if I have trouble swallowing them?

If swallowing pills is a problem for you, look for smaller pills, chewable products or vitamins in powder or liquid form. It's not a good idea to chew pills that are meant to be swallowed. Besides tasting horrible, many vitamin pills are designed with special coatings that boost the body's ability to absorb the nutrients.

Many multivitamins now add herbs and phytonutrients, such as lycopene. Is there any added benefit to these?

Maybe, but for now, it's probably not worth the extra money. Studies show that people who eat a lot of tomatoes, for example, have a lower risk of prostate cancer, and tomatoes are high in lycopene. But we don't know how our bodies react to synthetic versions of the nutrient, and vitamins may not contain enough to make a difference. Studies are looking into ginkgo's effect on memory, ginseng's ability to treat fatigue in cancer patients, and more. Some extras you might want to take: omega-3 fatty acids, to support heart health; lutein, to fight macular degeneration; and coenzyme Q10, to help lower cholesterol.

When should I take my vitamin?

Whenever it's easiest for you to remember. Certain vitamins — A, D, E and K — are fat-soluble, so taking your multi with food is a good idea.

Should everyone take a multivitamin?

Ideally, you should be able to get everything you need by eating a good diet, full of fruits and vegetables. If that's not possible (or if you live on junk), multivitamins work like an insurance policy. Vegetarians often miss out on some of the Bs. And everyone age 65 and older could probably benefit from a daily multivitamin, mostly because declining appetites and desensitized taste buds make it difficult to get enough of everything. It's a good idea to talk with your doctor before popping any pill. Some supplements can interact with each other in dangerous ways.

Where can I learn more about vitamins and minerals?

Here are some reliable sources: ; ; .

— Emily Sohn